Furnace-door-heating mechanism



April 2.7 1926. 1,582,128

F. T. COPE FURNACE DOOR HEATING MECHANISM Filed March 5, 1925 /4 1a /a m /w/ o v Q A? A-- Z I r I 14 a v y gwuenfoz fig/2k X 50,00

7 artql "c114,

Patented Apr. 27, 1926.

UNITED STATES 1, 2, 8 PATENT OFFICE.

FRANK T. COI E, 0F SALEM, OHIO, ASSIGNOR TO THE ELECTRIC FURNACE COMPANY, OF SALEM,- OHIO, A CORPORATION OF OHIO. I

FUBNACE-DOOR-HEATING MECHANISM.

Application filed March 5, 1925. Serial No. 13,184.

To all whom it may concern:

Be it known that I, FRANK T. Corn, a citizen of the United States, residing at Salem, in the county of Columbiana and State of Ohio, have invented certain new and useful Improvements in Furnace-Door- Heating Mechanism, of which the following is a specification.

This invention relates to electrically heated doors for electric furnaces and the objects of the invention are to provide means for mounting an electric resistor upon the inner surface of the door of an electric furnace, whereby the door may be opened without interrupting the circuit to the resistors upon the furnace walls; a further object being to rovide means whereby the circuit to the resistor upon the door is automatically broken when the door is opened, to prevent overheating of the furnace plate at the end of the furnace adjacentto the door.

The above and other objects may be attained by constructing the mechanism in the manner illustrated in the accompanying drawing, in which-- The figure is a vertical sectional view of the end portion of an electric furnace and door provided with heating means embodying the invention.

Similar numerals refer to similar parts throughout the drawing.

' One end portion of an-electric furnace is shown at 1, provided With a door openin 2 adapted to be closed by the vertically s 1dable door 3. Electric heating elements in the form of resistor grids are shown, diaammatically at 4 and 5 and adapted to fi located upon opposite side walls of the furnace.

The line wires 6 and 7 are connected to the ends of the grids 4 and 5 respectively.

The other end of each grid is connected by a wire 8 to one of the contact bars 9, each of said bars being pivotally suspended u on a link 10 supported upon the stationary ame 11 and arranged to be urged toward each other as by the sprin s 12.

A post' 13 is rigid y mounted upon the door and provided with a rigid arm 14 carrying an insulation plug 15 arranged to contact with and support the contact bars 9 when the door is in closed position. as shown in the drawing.

A contact p ate 16 is fixed u on each side of the tapered lower end of tie plug and arranged to engage the adjacent contact bar 9. A resistor grid 17 is mounted-upon the inner face of the door, each terminal 18' thereof being connected as by a flexible wire 19 with one of the contact plates 16. With the furnace door closed as shown in the drawing, the circuit will be completed from the line wires 6 through the grid 4 and adjacent wire 8, contact bar- 9, contact plate 16 and wire 19 through the resistor 17 upon the door, then through the other wire 19, contact plate 16, contact bar 9 and wire 8, through the resistor grid 5 and line wire 7.

When it is necessary to open thedoor to charge or empty the furnace, the raising of the door will move the plug 15 out of contact with the bars 9, the springs 12 moving said bars into contact with each other. ,No interruption of the circuit has occurred by this action as until the bars 9.were in contact, the circuit was being completed through the plates 16 and wires 19 to the door heating element.

As soon as the plug 15 is raised out of contact with the bars 9, the circuit to the door heating element 17 is broken. Thus while the door is in the opened or raised position, the heatin element thereon is out of circuit and over eating of the furnace the bars 9, supporting them and again completing the circuit through the heating ele- 'ment 17 u on the door.

With this construction, it will be seen that r the door may be opened and closed in order to charge or withdraw material from the furnace without interru ting the circuit to the resistors within the urnace and by providin the automatic switch, the circuit to the oor .resistor is automatically broken when the door is opened, preventing damage to the end plate of the furnace when the door is in the raised position, without cutting off the current to the resistors upon the side walls of the furnace.

I claim 1. An electric furnace including a resistor within the furnace, a movable door upon the furnace, a resistor carried upon the door, an electric circuit in which said reas the door is closed without interrupting the circuit to the resistor within the furnace. I 2. An electric furnace including a resistor within the-furnace, a movable door upon the furnace, a resistor carried upon the door, an electric circuit in which said resistors are normally located and means whereby the opening of the door breaks the circuit to the resistor upon the door without interrupting the circuit to the resistor within the furnace.

3. An electric furnace including a. movable door, a resistor carried upon the door, a circuit'for said resiston and means whereby the circuit is broken asthe door is opened and whereby the circuit is closed as the door is closed. 4

4. An electric furnace including a resistor within the furnace, a movable door upon the furnace,a resistor carried upon the door, an electric circuit in which the resistors are normally located,.and a switch in the cirwires connecting said contact cuit, operated by the movement of the door, to break the circuit to the resistor upon the door when the door is opened, without interrupting the circuit to the resistor within the furnace.

,5. An electric furnace including a pair of resistors within the furnace, a movable door upon the furnace, a resistor carried upon the door, a, contact plug carried by the door and provided with contact plates, flexible plates with the door resistor, a pair of spring pressed contacts connected to the furnace resistors and arranged to be separated by the plug and to be engaged by said contact plates when the door is closed, and means connecting the furnace resistors with a source of electric energy.

In testimony that I claim the above, I have hereunto subscribed my name.

FRANK r. COPE. 

